HipHop VM (HHVM) is a new open-source virtual machine designed for executing programs written in PHP. HHVM uses a just-in-time compilation approach to achieve superior performance while maintaining the flexibility that PHP developers are accustomed to. HipHop VM (and before it HPHPc) has realized a > 5x increase in throughput for Facebook compared with Zend PHP 5.2. HipHop VM is most commonly run as a standalone server, replacing both Apache and mod_php. WWW: https://github.com/facebook/hiphop-php/wiki